Ore jig dewatering device



May 4, 1954 E. VON BOLHAR ET AL ORE JIG DEWATERING DEVICE 2 Sheets-Sheet 1 Filed March 28, 1952 mw 0" Q w I a Q Q Z v mm, I x. \m m NM M\ Q m o N. pa a w l. w .T .v o o o o y 4, 1954 E. VON BOLHAR ET AL 2,677,463

ORE JIG DEWATERING DEVICE Filed March 28, 1952 2 Sheets-Sheet 2 FIG-J INVENTORS i064? Vd/V 50mm 6:024: 5 (NEVA i2 Patented May 4, 1954 UNITED STATES PATENT OFFICE- ORE: JIG DEWATERING DEVICE Edgar von Bolha1',Sausalito, and George F. Mar tinejz, Albany, Calif assignors to Yuba Mann-- facturing Company, a corporation Application March 28, 1952, Serial No. 279,032

6 Claims. 1

Our invention relates to means. for improving the operation of ore jigs placed in series relationship.

Ore jigs are customarily used to separate gold, platinum, tin and other values from the pulp, a heterogeneous mass comprising th-evalues, unwanted earth or sand materials and water. Separation is based upon the principle of differential rates of settling, througha fluid such as water, of particles having different specific gravities.

It has been found that more efiicient recovery results where the pulp is. allowed to flow onto a bed of shot or similar matcrial'located substantially at or just below the surface of water confined within a. container, the water then being pulsed or agitated in such a manner that the heavier values fall through the shot and down through the water to a point of collection at the bottom of the container. Owing to the higher velocity of fall of the heavier values as compared with the lighter unwanted material, the values are separated from the unwanted material. The values are removed from the-point of collection while the lighter unwanted material is carried ofi. by overflow to subsequent similar separation or to discharge. V I

An ore jig of this generalv nature is shown in a copendim application of one of the joint inventors herein, Serial No. 144,156, filed February 14, 1950. The embodiment therein; described illustrates a pair of ore jigs which are mounted in a parallel relationship.

It is sometimes found desirable to mount such ore jigs in a series arrangement so that the separation process is carried on consecutively over a multiplicity of ore jigs,- each of which subjects the pulp to a further. separation process, the discharge from one being the feed of the next.

In the operation of ore jigs of this type there is introduced into each cell or-hutch a quantity of water roughly equal in quantity'to the volume of pulp which enters the jig, Since but a relatively minor amount of values'are withdrawn from the jig, it may beseen that asthe'pulp proceeds in its: flow from one jig to another, the pulp becomes increasingly diluted: by reason of the addition of this make-up Water. It has been found that the decrease in the density of the pulp which results from this water lowers the eniciency of the recovery'process.

It has also been found that the 'addition'of this water into the pulp flow tends to cause stratification of the fluid and that recovery per jig is lessened at jigs subsequent to the first since, apparently, thexstratifiew p'ulp continues While a series arrangement of ore jigs is frequently the only relationship possible owing to the dredge hull or boat design it may" often be desirable that the operator be able to divert the entire flow discharging from one jig in the series in order, for example, to effect repairs or maintenance on subsequent jigs; or it may be desirable to divert a portion only of the discharge and to lead the undiverted portion to the next jig in the series to be there subjected to the separation procedure.

It is therefore an object of our invention to provide an ore jig dewatering device to permit the operator to divert a predetermined quantity or" the fluid flowing from one jig to the next.

It a further object of our invention to provide an ore jig dewatering device to permit the operator to send a diverted quantity of fluid now to another location for subsequent treatment or to overflow discharge.

A still furthe Object 'of our invention is to provide an ore jig dewatering device in which the entire discharge from the first ore jig may be diverted or in which the entire flow may be permitted to pass on to subsequent ore jigs.

A still further object of our invention is to provide an ore jig dewatering device in which that portion of the fluid flow which is not diverted. is caused to be mixed or to become un- Stratified. I

Another object of our invention is to provide an orc jig dewatering device eficctive to maintain a pulp density which is substantially constant throughout the flow. over the entire series of ore jigs. I I

A further object is to provide a device eifective over a wide range of pulpcomposition and operating conditions.

Another object of the invention isto provide a generally improved ore jig dewatering devicer Other objects, together with the foregoing, are attained in the embodiment of our invention described in the accompanying description and illustrated in the accompanying drawings in which:

Figure 1 is a plan of anore jig dewatering device installation in accordance with our invention.

- Figure 2 is a cross section on a vertical plane of the structure illustrated in Figure 1;, the left hand drive motor not being shown, in order to reduce the figure.

Figure 3 is a plan to an enlarged scale of an ore jig dewatering device in accordance with our invention.

Figure 4 is a cross section on a vertical plane. of the structure illustrated in Figure 3.

Ore jigs and ore jig dewatering devices of the type illustrated are customarily used in the separation of valuable materials from pulp which is placer mined, for example, by a dredge mounted on a dredge hull which floats in a pond. In such an installation there is provided a framework 6 which is made up of the usual angle irons and other structural shapes. The framework in the illustration shown provides two platforms i and 8 which are at different levels. On each platform is mounted a pair of ore jigs 9 and H respectively.

Each pair of ore jigs, for example jig pair 9, comprises two jigs i2 and i3. Since each pair of ore jigs is substantially identical except for location and some of the surrounding structure, a description of one pair applies equally to the other. Supported on platform l' are plates Id, I6, ll, 53, I19 and 2i defining the walls of the two jig cells or hutches in which the water is confined. Each cell is identical in construction but in position is in reverse symmetry with respect to the other. A common wall 22 separates one hutch from the other.

Jigs l2 and i3 also comprise screen grids 23 which rest on ledges 25 mounted near the tops of the hutches. Ihe grids 28 are held tightly in position by a plurality of swinging wedges 24 rotatably mounted on opposite walls ii and it. A layer of shot 29 rests upon the top side of the grid screens (the shot being shown only in jig l2). Bafile plates 26, one in each cell, extend downwardly and inwardly at an appropriate angle from opposite walls Hi and i6 and extend transversely from wall H to wall It.

Pulp is introduced into the first jig i2 by means of a chute 2? as shown by the arrow 36. Water is also introduced into each jig hutch through inlet pipes 28. in operation, a motor or other actuating device 3! causes a diaphragm z 32 to reciprocate or pulsate, flexibility of motion being provided by a flexible ring 33. By means of a yoke arrangement and yoke connecting rods (neither of which are shown) similar reciprocations are transmitted to a diaphragm 36 which causes agitation in the corresponding jig hutch 13. To obtain a continuous gravity now of the pulp, jig I3 is at a somewhat lower level than jig l2. Jig i3 is provided with a discharge weir or lip 36. Fluid, comprising pulp from which a portion of the values has been separated and water which has been introduced from inlet pipes 28, flows over the discharge lip 36, down a sloping connecting chute 31, and over the entrance lip an of following pair of ore jigs ii. The pulp is then subjected to further separation in jigs 38 and respectively, the residue discharging into a chute l! either to further ore jig separation or overboard through conduits not shown.

The sloping connecting chute Bl comprises a chute apron 42 and opposite side walls 63 and 44. Spaced vertically above and substantially parallel to the chute apron is provided a skimmer pan 46 which extends from one of the chute walls to the other. Piercing the center of the skimmer pan is a slot 41 having its downstream end located at substantially the lowest portion of the pan and extending in an upstream direction over a major portion of the width of the pan along the longitudinal axis of the chute. Depending from the skimmer pan is a drain pipe 48 contoured to conform with the outline of the slot. A skimmer pan wall 49 prevents fiow of fluids over the back of the pan. An outlet launder 5| below the chute apron is effective to receive and carry away fluid discharging from the drain pipe, as shown by an arrow 50.

In order to skim a predetermined portion of the fluid, for example a portion as shown by the arrow 55, discharging from the outlet lip 36 of the ore jig, we provide a skimmer blade 52, the upstream portion of which is contoured to ofier a sharp surface projecting into the oncoming stream of fluid. The skimmer blade extends from'one wall of the chute to the other and has, at the ends adjacent the walls, flanges 53 upstanding from the blade, each flange having an offset portion 54 which is arcuate in contour and which is slotted to receive a through bolt 55 in a bracket 5'1. The downstream edge of the skimmer blade is recurved to form a lip 53 resting in notched supports 59. The notched supports are affixed to the leading edge of skimmer pan 45 and act as pivots about which the skimmer blade may be rotated, the pivot axis being substantially horizontal.

The trailing edge of the skimmer blade is separated from the leading edge of the skimmer pan in order to provide a slot or channel 6%. The slot 69 allows a portion of the fluid skimmed by the skimmer blade to fall by gravity as shown by an arrow Si and to rejoin the fluid which is not skimmed but which is continuing on its course (indicated by an arrow 62) to the next lower jig. The effect of this return flow through the slot 69 is to create additional turbulence in the pulp traveling to the next lower jig (shown, for example, by an arrow 63) and thus materially to diminish any Stratification of pulp and water.

In operation, the operator determines what proportion of the-fluid flow he wishes to divert and, correspondingly, what part of the flow he wishes to send on for separation in the next ore jig. Then, by loosening the bolts 56 and placing the skimmer blade at the desired angle and again setting up on the bolts, he can set the blade to deflect a predetermined amount of the discharge.

The knife edge of the skimmer blade extending from one wall of the chute to the other slices the oncoming fluid into two substantially horizontal parallel layers. The top, skimmed layer travels over and across the top of the skimmer blade 52 and over the skimmer pan it. The fluid thus diverted by the skimmer blade and pan falls by gravity down the drain pipe 4'! into the outlet launder and is carried away for disposition elsewhere.

The balance of the fluid, that portion not so acted upon by the skimmer blade and pan, proceeds onwardly and by gravity flows down the sloping chute to furnish the inlet pulp for the following ore jig.

The skimmer blade may be set at an angle which is appropriate to maintain a substantially constant pulp density despite the addition of make-up water in the jig operation. Since the fluid discharging from the ore jig is comprised of substantially a light top layer and a denser bottom layer (the heavier pulp tending to gravitate downward and displace upwardly the lighter water) the skimming off of the upper layer is efiective to keep the lower layer at the desired higher density.

By permitting the knife edge to rest along discharge lip 36, the total quantity of discharging fluid can be diverted onto the skimmer blade and pan, and, except for the portion falling through the slot 60 between the blade and pan, is ultimately carried away by the outlet launder. By rotating the skimmer blade to its topmost position substantially all, if not all, of the discharge fiuid is directed into the connecting chute for entry into the next ore jig in the series.

Regardless of the composition of the incoming pulp, and despite the addition of substantial quantities of make-up water in the jig, the jig operator by an appropriate setting of our dewatering device can maintain the pulp in a desired condition for additional separation, not.

only as to density but in a proper state of turbulence. Likewise, he is also enabled to divert the entire discharge from an ore jig, or to allow, should conditions require it, the total discharge to proceed unskirnmed to the next ore jig in series.

What is claimed is:

1. An ore jig dewatering device comprising a pair of ore jigs having hut-shes; a sloping chute connecting said ore jigs adjacent the to of said hutches and adapted to conduct fluid from one of said ore jigs to the other; a horizontal skimmer blade rotatably mounted on a horizontal axis between the Walls of said chute; a skimmer pan disposed downstream from said skimmer blade and terminating substantially at said axis; and means for leading away from said other jig material skimmed by said blade and said pan from the upper portion only of said fluid.

2. An ore jig dewatering device comprising an inlet weir and an outlet weir; a sloping chute between said weirs having an apron and side walls; a skimmer blade mounted to rotate about a transverse axis normal to said walls and above said apron for adjustment to a predetermined angle; a skimmer pan mounted within said chute, said pan including a pan bottom above said apron and pan walls extending to said side walls; a

skimmer drain pipe depending from said skim mer pan through said apron in liquid tight engagement therewith; and an outlet launder mounted beneath said drain pipe. 7

3. An ore jig dewatering device comprising a pair of ore jigs; a sloping chute spanning the space between said ore jigs; a skimmer pan ex tending across said chute above the bottom thereof and having a leading edge; pivot supports,

disposed adjacent said leading edge of saidskimmer pan; a skimmer blade ahead of said leading edge v and contoured to engage with said pivot supports; a slotted flange upstanding from each end of said skimmer blade; a pair of brackets on opposite interior walls of said chute adapted to engage said flanges; and means for clamping said flanges to said brackets at predetermined positions.

4. An ore jig dewatering device comprising a plurality of ore jigs having hutches, a chute connecting said ore jigs adjacent the top of said hutches for fluid flow thereover in series; a skimmer pan dividing the chute into a lower portion and an upper portion and having an upstream edge; a skimmer blade extending upstream from the upstream edge of said skimmer pan, said blade being movable to predetermined positions for varying the fluid flow to said upper and to said lower portions; and meansfor diverting fluid from said upper portion away from said ore jig downstream in said series.

5. An ore jig dewatering device for use between a pair of jigs having hutches comprising a chute extending between said jigs adjacent the top of said hutches, means for causing fluid material to flow over one of said jigs then over said chute and then over the other of said jigs, means for adding water to said hutches of both of said jigs, and means in said chute for substantially diverting from said other of said jigs material constituting the upper portion only of said material flowing over said chute.

6. An ore jig dewatering device for use between an upstream jig and a downstream jig, each of said jigs having a substantially horizontal shot bed therein, a chute extending from adjacent the outlet edge of the shot bed in the upstream jig to adjacent the inlet edge of the shot bed in the downstream jig, means for supplying both of said jigs with water beneath said shot beds, a skimmer pan extending transversely across said chute and disposed above the bottom thereof, a drain pipe spanning the space between the bottom of said skimmer pan and the bottom or" said chute and out of communication with said chute, a skimmer blade movable into various positions and extending transversely across said chute upstream of said skimmer pan, and means for mounting said skimmer blade to act as a continuation of said skimmer pan in the various positions thereof.

References Cited in the file of this patent U UNITED STATES PATENTS Number Merchen Mar. 15, 1927 g 

